The present invention relates to a hollow golf club head, and more particularly to a golf club head including a combination of metal portions and fiber reinforced resin portions.
As wood type golf club heads such as driver or fairway wood type golf club heads, hollow metal golf club heads have been widely used. A hollow wood type golf club head generally includes a face portion for hitting a ball, a crown portion which constitutes an upper surface portion of the golf club head, a sole portion which constitutes a bottom surface portion of the golf club head, a side portion including toe-side, back-side, and heel-side side surface portions of the golf club head, and a hozel portion. A shaft is inserted to the hozel portion and is fixed there with an adhesive or the like. Note that very many golf clubs such as utility clubs have been recently marketed. As some types of such utility golf clubs, various types of golf clubs with a hollow head similar to the above-described wood type golf club head (i.e., a head including a face portion, a sole portion, a side portion, and a crown portion, and a hozel portion) have been marketed.
As metals constituting such hollow golf club heads, aluminum alloys, stainless steel, and titanium alloys have been used. In recent years, titanium alloys have been widely used in particular.
The sweet spot of a hollow golf club head can be expanded by increasing the volume of the head. When the volume of a golf club head is increased, its weight may also be increased. In order to prevent this, it has been proposed to employ fiber reinforced resins having specific gravities smaller than those of the above-described metals as constituent materials of golf club heads. Because it is necessary in this configuration that the surface of a face for hitting a ball be made of a metal to secure a sufficient strength, it is required that portions other than the face portion be made of fiber reinforced resins.
Japanese Patent Application Publication No. 2003-339920 discloses a golf club head including a metal face portion, and the other portions thereof are made of carbon fiber reinforced thermosetting resins.
Japanese Patent Application Publication No. 2006-130065 discloses that a hollow golf club head includes a face portion, a sole portion, a side portion, a crown portion, and a hozel portion, a main portion of the crown portion being made of a fiber reinforced resin; at least the face portion, a leading edge of the crown portion continuous with the face portion, and at least a center portion of the sole portion in a toe-heel direction being made of a metal; the loft angle being 14 to 25°; the volume of the head being 100 to 220 cc; and the weight of the fiber reinforced resin portion being 6 to 20% of the weight of the golf club head.
The fiber reinforced resin portions of the golf club head disclosed in Japanese Patent Application Publication No. 2003-339920 and Japanese Patent Application Publication No. 2006-130065 are produced by molding a laminate of prepreg sheets. Because such an operation for laminating prepregs takes time and labor, costs of manufacture of the golf club head according to the above-described conventional techniques may become high.